EP3859257B1 - Stopper for converter tap holes - Google Patents

Description

The invention relates to a sealing plug for temporarily closing the tap hole of a tiltable converter, consisting of a cylindrical, deformable plug body made of a mixture of clay, light bodies made of easily meltable hydrocarbon compounds, plasticizers and celluloses as well as oil as a molding aid, a base plate delimiting the plug body at the bottom, a base plate limiting the plug body at the top delimiting end plate and a tube connecting the two plates, the plug body being insertable via an applicator from the cold edge into the tap hole and being able to be fixed therein and flushed out of the tap hole again via the liquid steel.

In the blast furnace process, pig iron is first produced from iron ore using coke and lime. After being tapped in torpedo ladles, the pig iron is sent for further processing. The pig iron, which has been processed in the meantime, is then used in the converter to produce steel by blowing it with oxygen, with additives such as scrap and alloy materials usually being used for this purpose. These tiltable converters have an outlet opening or tap hole at a suitable point in the converter wall above the level of the steel bath for transferring the liquid steel into the tapping ladle. For emptying, the converter is tilted into such a position that the steel flows through the tap hole into the downstream ladle. Since the specifically lighter slag of different viscosity always floats on top of the molten steel, during the tipping process it is forced into the tap hole first and thus into the tapping ladle in more or less large quantities. For numerous subsequent metallurgical processes, that is The presence of oxygen-rich slag, often enriched with phosphorus or sulphur, is a significant disadvantage. There is therefore a requirement to transfer the converter steel to the tapping ladle with as little slag as possible. From the EP 0 635 071 a sealing plug is known in which the end plate is designed to transition into a funnel channel which perforates the sealing plug or the plug body and is shaped to accommodate a pulling claw acting on the end plate. The sealing plug is pushed into the converter tapping channel so far that its end plate is positioned almost flush with the inside of the converter and then set by pulling the claw. The end plate transitions into a funnel channel that penetrates the sealing plug, so that the plug is actually fixed on the inside of the converter and not on its outer wall. If the sealing plug is set accordingly, the end plate sinters and neither slag nor other parts can flow out through the tap hole, only the pure liquid steel. When the liquid steel comes into contact, the end plate and also the funnel channel or the tube defining it are partially melted, whereby the steel can flow in a targeted manner into the tapping ladle below. Such a sealing plug consists of refractory material, light bodies made of easily meltable hydrocarbon compounds, plasticizers, cellulose and oil. Depending on the size of the stopper, handling with the applicator or setting tool can be difficult. Depending on how long the sealing plug has been stored, deformation in the tap hole is also associated with problems, whereby the handling of the setting tool requires a certain skill, since this additional device with the pulling claw has to be recovered after the sealing plug has been set. From the EP 0 315 311 A1 a sealing plug is known which is arranged between the end plate and the base plate and consists of deformable material. A retaining plate supported on the inner wall of the converter offers a spring arrangement the possibility of displacing the base plate against the front plate on the manipulation rod and deforming the plug in the process. As a result, mortar escapes, which penetrates between the plug wall and the inner wall of the tap hole and into this fixes the stopper. The Japanese writing JP H 0 725 6437A describes a stopper made up of a cylinder formed by end-connected rods. When moving the ends of a rod, which runs in the middle of the rods and whose ends are joined together, the rods bend in the middle and a kind of barrel is created, which has a ring in the middle that attaches to the tap hole.

the U.S. 2011/014 8013 A1 concerns similar to the one described at the beginning EP 0 635 071 a closure plug that is inserted into the taphole with a complex setting device and fixed there by squeezing the deformable plug material. For this purpose, the end plate is pulled on the connecting tube with the aid of a pulling claw that forms the setting device in the direction of the base plate held in place by the setting device. During this fastening work, the sealing plug must be held in the tap hole by the employee in a free-floating position, with the employee working overhead. In the GB 25 34 231A a closure of the tap hole of a converter is described using a so-called slag shield, which is placed on the hot end of the tap hole from the inside of the converter. The slag shield or plate is connected to a rod which, in two solutions shown, has retaining parts or barbs at the ends. The rod with retaining parts is inserted into the taphole from the inside of the converter and then connected to the slag shield, which now cannot leave its position on the taphole because the retaining parts get stuck in the taphole and prevent the rod from being pulled out. Instead of the retaining parts and the plate, a truncated cone with "dart" is also provided, which fixes the plate in its position. Finally, a deformable plug body is disclosed, which is deformed in the taphole by a heat-expanding mass between the end plate and base plate until the plug body is firmly seated in the taphole and thus holds the slag shield in its covering position via a connecting rod.

The object of the invention is therefore to create a sealing plug which, due to its material composition, is easily deformable and which can be inserted into the taphole and deformed there without the complex setting device described.

According to the invention, the weight of the stopper body is reduced in a targeted manner by the light bodies that are used and, by using viscous oils, it is pushed into the taphole with a rod-shaped applicator and then fixed and deformed there by simply pushing it further, because the retaining claws get stuck when you push them in and with it that too Front plate, so that the base plate can be pushed towards the front plate, while at the same time the plug body is deformed by moving the two plates against each other. The retaining claws attach themselves to the tap hole, so that the plug body, which is already in the tap hole, can no longer be moved any further, but rather is inevitably deformed by the viscous oils.

According to an expedient embodiment of the invention, it is provided that the retaining claws are fixed to the end plate and that the base plate is designed to be displaceable on the tube via the rod-shaped applicator. This ensures that the end plate can no longer be moved further into the tap hole after the retaining claws have been fixed, but rather that the base plate located or arranged on the outside of the converter is now moved further into the tap hole, which ensures that that the plug body deforms and gets stuck in the tap hole.

A further advantageous embodiment provides that the retaining claws are fixed to the end plate and the base plate is connected to the tube and both can be displaced in the direction of the end plate via the rod-shaped applicator. This not only moves the base plate in the direction of the end plate, but also the pipe, which is then pushed through the end plate fixed by the retaining claws and thus protrudes a short distance into the tapping channel. This also ensures that the first slag does not flows through the tube and the slag escaping during the blowing process can also block it depending on its composition, but rather only and safely the liquid steel, which then, as already mentioned, dissolves both stopper components, but in any case prevents the slag from flows into the tapping ladle.

In a further development of this tube connected to the base plate, an expedient embodiment provides that the tube can be displaced via the applicator by 5-15 cm, preferably 10 cm, via the end plate in the direction of the converter interior. This is a great advantage, since the pipe can no longer become clogged with slag spraying out during the blowing process, leading to the disadvantages of clogging described above.

Instead of connecting, for example, welding the retaining claws to the end plate, an expedient embodiment of the invention provides for two retaining claws, connected to one another, to be placed on the displaceable end plate, encompassing the pipe above. If the end plate is now moved, the retaining claws ensure that this is not possible if the retaining claws have become stuck on the tap hole or in the tap hole.

Instead of the two retaining claws described, there is also the possibility that two, three or four retaining claws resting on top of the end plate are connected to one another and to the end plate or, as described above, simply rest on top without this connection. In this way, too, the mobility of the end plate can be prevented and the deformation process of the plug body can be effected with the lower base plate.

Depending on the design of the retaining claws, there is the possibility that they can get stuck in the tap hole or on the cold, outer edge of the tap hole.

Such fixing of the retaining claws is ensured if they are made of 6 mm reinforcing iron and are bent at the lower, free end to form the hook and have an external dimension of + 30 - 50 mm, preferably 40 mm larger than the plug circumference and 3 - 10 cm longer than the plug body are formed having. Because of these dimensions, it is first of all ensured that the upper end, which is either attached to the end plate or rests on it, can rest tightly against the plug body, i.e. it cannot impede the insertion process into the tap hole in any case. If the base body is then inserted far enough into the tap hole, the lower free ends with the hook will settle around the tap hole or around the cold outer edge, so that the deformation process can then begin safely. All this is done with the simple stick or applicator, so that skill can no longer play a decisive role here.

The plug body consists of the soft mass mentioned in claim 1, in particular also the mineral oil used and the light body, with a further development providing, in addition to these light bodies made of easily meltable hydrocarbon compounds, additional light bodies in the form of mineral ones to achieve a low overall weight and good handling Expanded glass existing hollow glass spheres are mixed with in the plug body. The plug body having these different lightweight bodies or additional lightweight bodies is characterized not only by a low overall weight, but also by the fact that it can be handled optimally and can therefore be easily introduced into the taphole. Finally, the contained mineral oil has an optimal shaping effect.

• 10 - 50 Vol.-% Polystyrolgranulat 10' von 0,3 - 5 mm,
• 5 - 30 Vol.-% Zusatzleichtkörper in Form von Blähglas von 0,2 - 8 mm ,
• 20 - 45 Gew.-% Zusatzleichtkörper in Form von Aluminiumhohlkugelsilikat mit 0,1 - 1,5 mm Durchmesser und
• 15 - 70 Gew.-% Tongemenge aus Kaolinit, Bentonit und Ton 3-Schichtsilikat,
• 0,5 - 3 Gew.-% Plastifizierer
• 0,1 - 2 Gew.-% Verflüssiger
• 0,1 - 2 Gew.-% temporäre Binder
• 0,1 - 5 Gew.-% permanente Binder und
• 2 - 8 Vol.-% Öle als Formhilfsmittel.

According to the invention, such a sealing plug has a plug body made from a mixture of

• 10 - 50% by volume polystyrene granulate 10' of 0.3 - 5 mm,
• 5 - 30% by volume additional light body in the form of expanded glass of 0.2 - 8 mm,
• 20 - 45% by weight additional light body in the form of hollow aluminum sphere silicate with a diameter of 0.1 - 1.5 mm
• 15 - 70% by weight clay mixture of kaolinite, bentonite and clay 3-layer silicate,
• 0.5 - 3% by weight of plasticizer
• 0.1 - 2% by weight liquefier
• 0.1 - 2% by weight temporary binder
• 0.1-5% by weight permanent binders and
• 2 - 8% by volume oils as molding aids.

The use of hollow glass spheres is basically from the EP 2 315 859 B1 known, but not in the material composition specified here and also not together with polystyrene granulate of 0.3 - 5 mm, which, however, only brings the desired optimal weight reduction and thus optimal ease of handling in this composition and, moreover, together with the specific clay and Bentonite gives the mass the necessary softness.

It is advantageous and according to the invention also specifically to provide to mix the stopper with the polystyrene granules mentioned, but in the form of 2 - 3 mm, while the expanded glass in the form of 0.2 - 0.5 mm and the hollow aluminum sphere silicate in the Shape of 0.1 - 0.5 mm is introduced into the overall mixture. The polystyrene should not have a spherical shape. This shape gives the polystyrene a modified structure which, together with the expanded glass, gives the stopper a high level of stability. The specifically shaped polystyrene gives the mass or the mixture a much better hold than the polystyrene beads previously used, because the new shape (coffee bean shape) creates a matrix similar to that of a concrete mixture. In this way, the desired stability can be reliably achieved and maintained.

The polystyrene granules should also be a graphitized polystyrene according to the invention, this graphitized styrofoam for an optimal good mixing and adhesion of all components of the stopper body. Such a sealing plug ensures quick installation, ensures that the preliminary slag is always held back, even while the converter is tilting, sits securely in the taphole, does not sinter and ensures that the channel is completely free within 5 to 10 seconds at the moment of tapping , so that the steel can flow out. The stopper can be stored well and is light in weight, which makes it particularly easy to insert into the converter's tap hole. At the moment of the start of tapping, the sealing plug according to the invention ensures a sufficiently high steel bath above the plug by briefly retaining the steel, so that tapping vortices can be reliably prevented. These disadvantageous vortices occur with bath heights of less than 2.5 times the tapping diameter, i.e. with a tapping of 160 mm below a height of 400 mm. If there is no sealing plug, vortices are created which move through the bath to the surface and pull converter slag into the receiver or the tapping ladle during tapping.

Figur 1

einen gekippten Konverter während des Auslaufens des flüssigen Stahls,

Figur 2

den Stand der Technik mit einem Setzgerät,

Figur 3

einen Verschlussstopfen mit vier Haltekrallen,

Figur 4

eine Seitenansicht eines Verschlussstopfens mit ausgefahrenem Rohr,

Figur 5

einen Verschlussstopfen mit zwei das Rohr umfassende Haltekrallen,

Figur 6

einen Verschlussstopfen, bei dem die Haltekrallen mit dem Stirnblech verbunden sind und dem Grundblech, das auf dem fest mit dem Stirnblech verbundenen Rohr verschiebbar ist,

Figur 7

einen Schnitt durch ein Abstichloch mit einem eingesetzten Verschlussstopfen und am kalten Rand des Abstichsloches sich festsetzenden Haltekrallen,

Figur 8

einen Schnitt durch ein Abstichloch mit eingebrachtem Verschlussstopfen und Haltekrallen, die sich im Abstichloch festgesetzt haben und

Figur 9

graphitierte und kaffeebohnenartig ausgebildete Leichtkörper aus Styropor.

Further details and advantages of the subject of the invention result from the following description of the associated drawing, in which a preferred exemplary embodiment is shown with the necessary details and individual parts. Show it:

figure 1

a tilted converter during liquid steel discharge,

figure 2

the state of the art with a setting tool,

figure 3

a sealing plug with four retaining claws,

figure 4

a side view of a sealing plug with the tube extended,

figure 5

a sealing plug with two retaining claws surrounding the pipe,

figure 6

a sealing plug, in which the retaining claws are connected to the end plate and the base plate, which can be slid on the tube fixed to the end plate,

figure 7

a cut through a tap hole with a sealing plug inserted and retaining claws attached to the cold edge of the tap hole,

figure 8

a section through a tap hole with a sealing plug and retaining claws that have become stuck in the tap hole and

figure 9

Graphite and coffee bean-like lightweight body made of polystyrene.

figure 1 shows a converter 2 in section, it being seen that the outflowing liquid steel 5 carries a layer of slag 6. The liquid steel 5 flows through the tap hole 4 into the tapping ladle 3, which is already partially filled with liquid steel 5'. The sealing plug 1 is in here figure 1 not shown and not recognizable because it has already been flushed out of tap hole 4 by the liquid steel. The interior of the converter is denoted by 18 and the cold edge of the tap hole 4 is denoted by 24. These reference numerals will be discussed further below.

figure 2 actually shows the state of the art, in which the sealing plug 1 is inserted with its entire plug body 8 into the tap hole 4 in order to then be deformed by the setting device 22, for which purpose the base plate 11 and end plate 12 are moved towards one another with the setting device 22, 22' will. As a result, the wall of the plug body 8 is pressed against the inner wall of the tap hole 4 and the tap hole 4 is thus effectively closed. After the setting device 22 has been removed, after the converter 2 has been tilted accordingly, liquid steel can flow through the pipe 13 as shown in FIG figure 1 shown to disperse in tapping ladle 3.

figure 3 shows an embodiment of the sealing plug 1 with the plug body 8, which is covered by the end plate 12 at the end to be introduced first into the tap hole 4. This end plate 12 is connected to 4 retaining claws 15, 16, 20, 21, these retaining claws 15, 16, 20, 21 with their hooks 26, 26' ensure that the plug body 8 is fixed there on the inner wall 7 or on the cold edge of the tap hole 24 after it has been inserted into the tap hole 4 . Below the base plate 11 is not visible, but the protruding tube 13, the base plate 11 and end plate 12 connects.

figure 4 shows an embodiment in which only two retaining claws 15, 16 are used, which have hooks 26, 26' at the lower end, ie at the free end 25. The retaining claws 15, 16 are firmly fixed to the upper end plate 12, while the displaceable mass 30 with the lower loose base plate 11 can be pushed against the upper end plate 12, which is firmly connected to the tube 13, so that the outer wall 27 of the plug body 8 is tight the inner wall 7 of the tap hole 4 can create.

In this embodiment, the stopper body 8 has polystyrene granulate in addition to the quantity of clay

The sealing plug after figure 5 is characterized in that the two retaining claws 15, 16 are looped around the tube 13 above the end plate 12 and connected to one another, so that a fixation, ie a connection to the end plate 12, can be dispensed with. The tube 13 has an overhang 14 here, which is created by the pipe being pushed through the end plate 12 in order to reach the overhang 14 already mentioned earlier, and this can take place when the plug body 8 is deformed. As a result, slag 6 cannot flow through the pipe 13 and close it, since the pipe 13 protrudes about 10 cm at the top towards the hot side and no slag 6 may then build up in the pipe 13 . Otherwise, if the pipe 13 does not protrude during the blowing process, it would easily become clogged with slag spraying out, which would later cause problems when the liquid steel 5 tipped out or ran out.

figure 6 turn shows an embodiment in which the braces 15, 16 are connected to the end plate 12, wherein the tube 13 together with the Base plate 11 is moved in the direction of the end plate, so as to fix the plug body 8 in the tap hole 4. In this embodiment, it is characteristic that the plug body, in addition to the clay mixture 9 and the light bodies 10, 10 ', also has additional light bodies 28, 28', 28 ", which are introduced into the mixture. The additional light bodies 28' consist of sodium / calcium spherical silicate and the Additional lightweight body 28" made of aluminum ball silicate, so that overall a mixture is created as specified in claim 11. In this context, it should also be pointed out that the lightweight polystyrene granules consist of graphitized polystyrene and have the aforementioned coffee bean shape.

In the Figures 7 and 8 a rod-shaped applicator 17 is shown, with which the plug body 8 can be inserted into the tap hole 4 . Since the plug body 8 is equipped with the retaining claws 15, 16 shown in both figures, which have hooks 26, the plug body 8 settles when it reaches the position of figure 7 or. figure 8 fixed in the tap hole 4, in which case either the base plate 11 is moved in the direction of the end plate 12 or the end plate 12 in the direction of the base plate 11. Again, the supernatant 14 is here figure 8 recognizable and an auxiliary unit that should not really be described as a setting device 22, but rather the already mentioned rod-shaped applicator 17.

figure 9 then shows the light bodies 10, 10', 10" mentioned several times, with the coffee bean shape being particularly noteworthy here. In addition, these light bodies 10 are characterized by their black color, which is the result of graphitization. It can be seen that the surface of these light bodies 10 is not quite flat, but rather shows notches, edges and the like, which facilitates attachment to the clay mixture 9 .

In figure 1 the tap hole 4 is shown with its two edges. On the inside, ie on the liquid steel 5, the warm edge 23 can be seen, while the cold edge, which has already been mentioned, is denoted by 24. at figure 5 the enclosing of the ends of the retaining claws 15, 16 is identified by the reference numeral 19.

Claims (13)

1. Plug for a temporary closure of the tap hole (4) of a tilting converter (2), consisting of a cylindrical, malleable plug body (8) consisting of a clay mixture (9), lightweight bodies (10) consisting of easily meltable hydrocarbon compounds, plasticizers and celluloses as well as oil as a moulding aid, a base plate (11) limiting the plug body (8) underneath, a end plate (12) limiting the plug body (8) above and a pipe connecting both plates (13), whereby the plug body (8) can be introduced into the tapping hole (4) from the cold edge (24) via an applicator (17) and fixed in it and is washed out of the tap hole (4) via the liquid steel (5), characterized in that
   the plug body (8) is easily malleable as a soft mass through the addition of viscous oils and that it is provided with retaining claws (15, 16), which are shaped to attach themselves to the inner wall (7) of the tapping hole (4) with their hooks (26, 26') when the plug body (8) is inserted, whereby the base plate (11) is then movable in the direction of the end plate (12) connected with retaining claws (15, 16) and thereby a distortion of the plug body (8) between base plate (11) and end plate (12) is carried out with the help of the rod-shaped applicator (17').
2. Plug according to claim 1,
   characterized in that
   the retaining claws (15, 16) are fixed to the end plate (12) and that the base plate (11) is designed to slide over the rod-shaped applicator (17) on the pipe (13).
3. Plug according to claim 1,
   characterized in that
   the retaining claws (15, 16) are fixed to the end plate (12) and the base plate (11) is connected to the pipe (13) and both can be moved via the rod-shaped applicator (17) in the direction of the end plate (12).
4. Plug according to claim 3,
   characterized in that
   the pipe (13) can be moved via the applicator (17) by 5 - 15 cm, preferably 10 cm over the end plate (12) towards the converter interior (18).
5. Plug according to claim 2,
   characterized in that
   two retaining claws (15, 16) are interconnected above the pipe (13) and placed surrounding the sliding end plate (12).
6. Plug according to claim 2,
   characterized in that
   two, three or four retaining claws (15, 16, 20, 21) are connected to each other and to the end plate (12).
7. Plug according to claim 1,
   characterized in that
   the retaining claws (15, 16, 20, 21) are designed to attach themselves firmly in the tapping hole (4) or on the cold, outer edge (24) of the tapping hole (4).
8. Plug according to claim 1,
   characterized in that
   the retaining claws (15, 16, 20, 21) are made of 6 mm reinforcing bars and at the lower, free end (25) are curved to form the hook (26, 26') and are designed with an outer dimension of + 30 - 50 mm, preferably 40 mm greater than the plug circumference and a length 3 - 10 cm greater than the plug body (8).
9. Plug according to claim 1,
   characterized in that
   in addition to lightweight bodies (10) from easily meltable hydrocarbon compounds to achieve a low total weight the plug body (8) is designed containing additional lightweight bodies (28) in the form of hollow mineral glass balls (28', 28") consisting of expanded glass.
10. Plug according to claim 1,
    characterized in that
    the plug body (8) is formed from of a mixture of

    10 - 50 vol% poystyrene granules (10') of 0.3 - 5 mm,

    5 - 30 vol% additional lightweight bodies (28') in the form of sodium / calcium hollow ball silicate of 0.2 - 8 mm,

    20 - 45 wt% additional lightweight bodies (28 ") in the form of aluminum hollow ball silicate with 0.1 - 1.5 mm diameter and

    15 - 70 wt% clay mixture (9) consisting of kaolinite, bentonite and clay 3-layer silicate,

    0.5 - 3 wt% plasticizer

    0.1 - 2 wt% condenser

    0.1 - 2 wt% temporary binder

    0.1 - 5 wt% permanent binders and

    2 - 8 vol% oils as a moulding aid
11. Plug according to claim 10,
    characterized in that
    the polystyrene granules (10') in the form of 2 - 3 mm, the expanded glass (28') in the form of 0.2 - 0.5 mm diameter, the hollow aluminium ball silicate (28") in the form of 0.1 - 0.5 mm diameter form the plug body (8) with the additional mixture components.
12. Plug according to claim 10,
    characterized in that
    the polystyrene granules (10') have an irregular coffee bean shape.
13. Plug according to claim 10,
    characterized in that
    the polystyrene granule (10') is a graphitized polystyrene.

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